The long term objective of this proposed research project is to demonstrate the therapeutic benefits, both physical and psychosocial, of a readily useable mobile prone board which can be self-propelled by disabled children. The specific aims of Phase I are to: 1) assesses the neuromuscular and musculoskeletal benefits of using the mobile prone board with disabled children; 2) refine the prototype design based on the functional needs of the disabled children. Clinical testing of young children with Cerebral Palsy in Phase I will assess changes in posture, range of motion of joints gross motor skills, ability to propel the device, and behavioral changes before and after using the device. Ease of assembly and disassembly of the device will be measured. Engineers will administer a thorough stress analysis of the device to insure safety prior to the start of the clinical trials. Findings from Phase I will demonstrate the feasibility of pursuing further research and development (Phase II) and will provide data to guide further study with other diagnoses of disabled children in various environments.